The present invention relates to fuel injection systems for internal combustion engines, and more particularly the invention relates to a fuel injection system in which the operation of a fuel control unit for distributing and metering fuel is electro-hydraulically controlled in response to the signals from various sensors.
A fuel injection system of the above type is known in the art which includes a measuring plate positioned in the intake pipe of an engine so as to be displaced in response to the amount of air flow, whereby the displacement of the measuring plate is transmitted to a plunger through a mechanical link mechanism and the plunger is moved axially, thereby effecting the distribution and metering of the fuel.
A disadvantage of this known system is that the air flow sensor including the measuring plate is made integral with the fuel control unit for distributing and metering fuel, thus increasing the size of the system and thereby deteriorating the ease of mounting and installing the system in the limited engine room of automobiles or the like.
Another disadvantage is that since the air flow sensor and the fuel control unit are mechanically coupled, where it is desired to effect the closed loop control of air-fuel ratio by means of an oxygen sensor or it is desired to correct the fuel quantity supplied by means of an engine cooling water temperature sensor, the construction prevents the electric detection signal of the sensor from being reflected in the control system.